Adenosine Mediated Modulation of Cardiac Fibrosis

腺苷介导的心脏纤维化调节

• 批准号: 6612815
• 负责人: Francisco J Villarreal
• 金额: $ 34.2万
• 依托单位: UNIVERSITY OF CALIFORNIA, SAN DIEGO
• 依托单位国家: 美国
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-07-15 至 2006-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6612815
• 关键词: adenosine; adenosine kinase; angiotensin receptor; cell proliferation; collagen; cyclic AMP; cyclic GMP; echocardiography; extracellular matrix; fibroblasts; fibrogenesis; fibrosis; genetic transcription; green fluorescent proteins; heart cell; heart failure; heart function; kinase inhibitor; laboratory mouse; laboratory rat; myocardial infarction; myocardium disorder; protein biosynthesis; purinergic receptor; scars; tumor necrosis factor alpha

Myocardial fibrosis can contribute to diastolic dysfunction and the development of heart failure. Preliminary results indicate that adenosine (ADO) can inhibit cardiac fibroblast (CF) function. These effects appear mediated via ADO A2b receptors. We will test the hypothesis that: "The enhancement of myocardial adenosine levels reduces the synthesis of cardiac collagens and associated fibrosis through the stimulation of cardiac fibroblast adenosine A2b receptors". We will examine the following aims: AIM 1: Enhanced myocardial ADO levels in the setting of myocardial infarction (MI) inhibits the deposition of cardiac collagens. We will induce the acute deposition of cardiac collagens in rats via MI induced scar formation. To enhance tissue ADO levels we will use the ADO kinase inhibitor compound GP515. We will assess for the functional consequences of the inhibition of scar formation in control untreated and treated MI rats by determining passive and active structure-function and by analysis of the microstructural properties of the scar. AIM 2: Enhanced myocardial ADO levels in the setting of MI reduces in vivo cardiac fibroblast proliferation and type I collagen gene transcription. We will use MI to induce cardiac fibroblast proliferation and collagen deposition in transgenic mice that link the expression of the marker green fluorescent protein (GFP) to collagen type I (CI- GFP) gene expression. Myocardial ADO levels will be enhanced as in aim 1. In vivo CF proliferation, type I gene expression and cardiac function, scarring/remodeling will be assessed at predetermined time points. AIM 3: The absence of A2b receptors in the MI mouse heart impairs the ability of ADO to diminish cardiac collagen synthesis yielding enhanced scar deposition. We will use mice null (-/-) for A2b receptors. We will induce the acute deposition of cardiac collagens in wild type and in A2b receptor null mice by using MI. Tissue ADO levels will be enhanced as in aim 1. Cardiac passive and active structure- function will be assessed at predetermined time points. The effects of enhanced ADO levels will also be examined in vitro using cultured CF from A2b (-/-) mice and assessing for ADO modulation of cell function. AIM 4: ADO inhibits TNF-alpha release and cardiac fibroblast function through the stimulation of A2b receptors and associated increases in cAMP and/or cGMP levels. We will assess for adenosine A2b receptor mediated induced inhibition of CF function and for the role of intracellular cAMP and/or cGMP in mediating ADO induced alterations in CF function.

心肌纤维化可导致舒张功能障碍和心力衰竭的发展。 初步结果表明，腺苷（ADO）可以抑制心脏成纤维细胞（CF）功能。 这些作用似乎是通过 ADO A2b 受体介导的。 我们将检验以下假设：“心肌腺苷水平的增强通过刺激心脏成纤维细胞腺苷 A2b 受体来减少心脏胶原蛋白的合成和相关纤维化”。 我们将研究以下目标： 目标 1：心肌梗塞 (MI) 情况下心肌 ADO 水平的增强会抑制心肌胶原蛋白的沉积。 我们将通过心肌梗死诱导的疤痕形成来诱导大鼠心脏胶原蛋白的急性沉积。 为了提高组织 ADO 水平，我们将使用 ADO 激酶抑制剂化合物 GP515。 我们将通过确定被动和主动结构功能并分析疤痕的微观结构特性，评估未治疗和治疗的对照 MI 大鼠中疤痕形成抑制的功能后果。 目标 2：MI 情况下心肌 ADO 水平升高会减少体内心脏成纤维细胞增殖和 I 型胶原基因转录。 我们将使用 MI 诱导转基因小鼠心脏成纤维细胞增殖和胶原蛋白沉积，将标记绿色荧光蛋白 (GFP) 的表达与 I 型胶原蛋白 (CI-GFP) 基因表达联系起来。 心肌 ADO 水平将如目标 1 中那样增强。将在预定时间点评估体内 CF 增殖、I 型基因表达和心脏功能、疤痕形成/重塑。 目标 3：MI 小鼠心脏中 A2b 受体的缺失会损害 ADO 减少心脏胶原蛋白合成的能力，从而增强疤痕沉积。 我们将使用 A2b 受体无效 (-/-) 的小鼠。 我们将通过使用 MI 来诱导野生型和 A2b 受体缺失小鼠中心脏胶原蛋白的急性沉积。 将按照目标 1 提高组织 ADO 水平。将在预定时间点评估心脏被动和主动结构功能。 还将使用 A2b (-/-) 小鼠培养的 CF 在体外检查增强 ADO 水平的影响，并评估 ADO 对细胞功能的调节。 目标 4：ADO 通过刺激 A2b 受体以及相关的 cAMP 和/或 cGMP 水平增加来抑制 TNF-α 释放和心脏成纤维细胞功能。 我们将评估腺苷 A2b 受体介导的 CF 功能诱导抑制以及细胞内 cAMP 和/或 cGMP 在介导 ADO 诱导的 CF 功能改变中的作用。